Conventionally prepared samples are annealed at a carefully controlled constant temperature and oxygen pressure. The physical properties of these conventional samples are then investigated through various measurements on a series of samples prepared under varied annealing conditions so as to have discretely varied oxygen content. It would be advantageous to have a system and method to prepare such a sample so that the oxygen content is controllably varied physically within the same sample. With such a sample, it would be possible to perform electronic transport measurements over micro- to nano-scale regions having significantly smaller differences in oxygen content, leading to a greatly improved characterization of the evolving physical properties under study.